Plywood 101 (part 1)

Lamination is a four-letter word in the consumer’s mind today. This is largely because so many people have been screwed over by poor laminates over secondary substrates. Ply, as it applies here, is a single thickness, fold or layer. Our plywood is referred to as hardwood plywood. This is because the substrate is made up of layers of hardwood. Specifically, poplar, basswood and luan are some of the woods used to make up the core.

Other plywood cores are made up of particle board, straw board, wheat board and medium density fiberboard (MDF). These are often viewed as inferior because they don’t last very long. There is far less strength associated with these other cores because they are not laminated (except MDF). Lamination is simply the process of building up something in thin sheets or layers. Ply is therefore the thing, and lamination is the process.

Layers of ply are oriented at right angle to each other. When you look at the end of one of our adjustable shelves, you see dark and light alternating colors. What you are seeing are the alternating grains. End grain is darker than long grain. This is what makes plywood strong and stable. In this case “stable” means that it doesn’t expand and contract nearly as much as solid hardwood does, making it in some ways, a more versatile material.

The top coating on plywood is called the veneer. The wood veneer that is applied to the surface of plywood is about 1/32 inches thick. Each strip of veneer you see on the plywood is referred to as flitch. The seams are called flitch seams. The flitch pattern should be a perfect match, much like the book matching on our doors, done over and over again. Another veneer process, though less common, is called rotary cut veneer. This would be like rolling a log with a knife against it, peeling up the wood in a solid continuous sheet. This is a more sophisticated machining process, as you can imagine.

In part 2 of this series, we’ll explain more about plywood and how it functions in good quality furniture.

In the meantime, here’s a video from Bob Vila about how plywood is made.

http://video.bobvila.com/m/21319559/making-birch-veneer-plywood.htm